.site-header {
    background: var(--header-bg);
    color: var(--brand-color);
    height: var(--header-height);
    padding: 12px 20px;
    border-bottom: 3px solid var(--brand-color);
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1100;
    transition: transform 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
}

.site-header.is-fixed {
    position: fixed;
    background: var(--header-bg-fixed);
    box-shadow: 0 10px 24px rgba(29, 70, 151, 0.16);
}

.site-header.is-hidden {
    transform: translateY(calc(-1 * var(--header-height)));
}

.header-inner {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    gap: 18px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--brand-color);
    text-decoration: none;
    font-weight: 700;
    flex: 0 0 auto;
}

.brand span {
    line-height: 1.02;
    font-size: 23px;
}

.brand img {
    width: 60px;
    height: auto;
    object-fit: contain;
    border-radius: 6px;
    background: var(--color-white);
}

.main-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 18px;
    flex-wrap: wrap;
    margin-left: auto;
    margin-right: auto;
}

.main-nav a {
    color: #000;
    text-decoration: none;
    font-size: 18px;
    font-weight: 700;
    padding: 6px 8px;
    border-bottom: 2px solid transparent;
}

.main-nav a.is-active {
    border-bottom-color: #000;
}

.contact-btn {
    background: var(--button-bg);
    color: var(--button-text);
    border: 1px solid var(--button-border);
    border-radius: 4px;
    padding: 8px 14px;
    line-height: 1.1;
    font-size: 15px;
    border-bottom-width: 1px;
}

.contact-btn.is-active {
    border-bottom-color: var(--button-border);
    box-shadow: inset 0 -2px 0 var(--button-border);
}

.social-links {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
    flex: 0 0 auto;
}

.social-links a {
    width: 34px;
    height: 34px;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--color-white);
    color: var(--brand-color);
    border: 1px solid var(--brand-color);
    transition: background-color 0.2s ease, color 0.2s ease;
}

.social-links a:hover {
    background: var(--brand-color);
    color: var(--color-white);
}

.social-links svg {
    width: 18px;
    height: 18px;
    fill: currentColor;
}

.mobile-social {
    display: none;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    width: 40px;
    height: 40px;
    border: 1px solid var(--brand-color);
    border-radius: 8px;
    background: var(--color-white);
    margin-left: auto;
}

.menu-toggle-bar {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--brand-color);
    margin: 0 auto;
    transition: transform 0.2s ease, opacity 0.2s ease;
}

.menu-toggle.is-open .menu-toggle-bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
}

.menu-toggle.is-open .menu-toggle-bar:nth-child(2) {
    opacity: 0;
}

.menu-toggle.is-open .menu-toggle-bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
}

@media (max-width: 1700px) {
    .brand span {
        font-size: 24px;
    }

    .main-nav {
        gap: 10px;
    }

    .main-nav a {
        font-size: 16px;
        padding: 5px 6px;
    }

    .contact-btn {
        padding: 7px 12px;
        font-size: 14px;
    }
}

@media (max-width: 1350px) {
    .site-header {
        padding: 10px 14px;
    }

    .header-inner {
        justify-content: space-between;
        gap: 10px;
    }


    .brand span {
        font-size: 22px;
        line-height: 1;
    }

    .menu-toggle {
        display: inline-flex;
        position: relative;
        z-index: 60;
    }

    .main-nav {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--menu-mobile-bg);
        z-index: 1050;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 16px;
        padding: 24px;
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transform: translateY(-8px);
        transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
        margin: 0;
    }

    .main-nav a.is-active {
        border-bottom-color: transparent;
    }

    .main-nav.is-open {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transform: translateY(0);
    }

    .main-nav a {
        color: var(--menu-mobile-link);
        border-bottom-color: transparent;
        font-size: 22px;
        line-height: 1.3;
        text-align: center;
        width: 100%;
        max-width: 480px;
    }

    .main-nav a.is-active {
        text-decoration: underline;
    }

    .main-nav .contact-btn {
        color: var(--brand-color);
        border: 1px solid var(--button-border);
        padding: 10px 16px;
        font-size: 18px;
    }

    .desktop-social {
        display: none;
    }

    .mobile-social {
        display: flex;
        margin-top: 20px;
        gap: 22px;
        justify-content: center;
    }

    .mobile-social a {
        color: var(--menu-mobile-link);
        border-color: var(--menu-mobile-border);
        background: transparent;
    }

    .mobile-social a:hover {
        background: var(--menu-mobile-link);
        color: var(--menu-mobile-bg);
    }
}